North Korea has warned the West it will cancel the 1953 armistice pact because of sanctions and joint US-South Korean military drills.

The Korean People's Army supreme command said the ceasefire would be torn up amid reports that the US and China have approved draft resolutions to punish Pyongyang for its third nuclear test.

The draft will go to UN Security Council members who condemned the tests and vowed to take action against Pyongyang.

In January, it passed a resolution widening UN sanctions against North Korea and warned Pyongyang against further missile launches.

The truce still technically prevents North Korea and the US resuming the three-year war, as no peace treaty has ever been signed.

Both sides regularly accuse the other of violating the agreement, which suspended open hostilities, provided a fixed demilitiarised zone along the border between North and South Korea, and set up a mechanism to transfer prisoners of war.

Both sides pledged not to "execute any hostile act within, from, or against the demilitarised zone" or enter areas under control of the other.